N-Substituted Imidazopyridine c-Kit Inhibitors

ABSTRACT

Compounds represented by Formula (I): 
     
       
         
         
             
             
         
       
     
     or a pharmaceutically acceptable salt or N-oxide thereof, are useful in the treatment of cancer.

BACKGROUND OF THE INVENTION

The present invention is directed to N3-substituted imidazopyridinecompounds. In particular, the present invention is directed toN3-substituted imidazopyridine compounds that are inhibitors of c-Kitproto-oncogene (also known as KIT, CD-117, stem cell factor receptor,mast cell growth factor receptor).

The c-Kit proto-oncogene is believed to be important in embryogenesis,melanogenesis, hematopoiesis, and the pathogenesis of mastocytosis,gastrointestinal tumors, and other solid tumors, as well as certainleukemias, including AML. Accordingly, it would be desirable to developnovel compounds that are inhibitors of the c-Kit receptor.

Many of the current treatment regimes for hyperproliferative disorders(cancer) utilize compounds that inhibit DNA synthesis. Such compounds'mechanism of operation is to be toxic to cells, particularly to rapidlydividing tumor cells. Thus, their broad toxicity can be a problem to thesubject patient. However, other approaches to anti-cancer agents thatact other than by the inhibition of DNA synthesis have been explored totry to enhance the selectivity of the anti-cancer action and therebyreduce adverse side-effects.

It is known that a cell may become cancerous by virtue of thetransformation of a portion of its DNA into an oncogene (i.e. a genewhich, on activation, leads to the formation of malignant tumor cells).Many oncogenes encode proteins that are aberrant protein-tyrosinekinases capable of causing cell transformation. By a different route,the overexpression of a normal proto-oncogenic tyrosine kinase can alsoresult in proliferative disorders, sometimes resulting in a malignantphenotype. Alternatively, co-expression of a receptor tyrosine kinaseand its cognate ligand within the same cell type may also lead tomalignant transformation.

Receptor tyrosine kinases are large enzymes which span the cell membraneand possess i) an extracellular binding domain for growth factors suchas KIT ligand (also known as stem cell factor (SCF), Steel factor (SLF)or mast cell growth factor (MGF)), ii) a transmembrane domain, and iii)an intracellular portion which functions as a kinase to phosphorylatespecific tyrosine residues in proteins. Binding of KIT ligand to KITtyrosine kinase results in receptor homodimerization, the activation ofKIT tyrosine kinase activity, and the subsequent phosphorylation of avariety of protein substrates, many of which are effectors ofintracellular signal transduction, These events can lead to enhancedcell proliferation or promote enhanced cell survival. With some receptorkinases, receptor heterodimerization can also occur.

It is known that such kinases are frequently aberrantly expressed incommon human cancers such as breast cancer, head and neck cancers,gastrointestinal cancer such as colon, rectal or stomach cancer,leukemia, and ovarian, bronchial, lung or pancreatic cancer. KIT kinaseexpression has been documented in a wide variety of human malignanciessuch as mastocytosis/mast cell leukemia, gastrointestinal stromal tumors(GIST), small cell lung carcinoma (SCLC), sinonasal naturalkiller/T-cell lymphoma, testicular cancer (seminoma), thyroid carcinoma,malignant melanoma, ovarian carcinoma, adenoid cystic carcinoma, acutemyelogenous leukemia (AML), breast carcinoma, pediatric T-cell acutelymphoblastic leukemia, angiosarcoma, anaplastic large cell lymphoma,endometrial carcinoma, and prostate carcinoma. The kinase activity ofKIT has been implicated in the pathophysiology of several of these—andadditional tumors—including breast carcinoma, SCLC, GIST, germ celltumors, mast cell leukemia, neuroblastoma, AML, melanoma and ovariancarcinoma.

Several mechanisms of KIT activation in tumor cells have been reported,including activating mutations, autocrine and paracrine activation ofthe receptor kinase by its ligand, loss of protein-tyrosine phosphataseactivity, and cross activation by other kinases. The transformingmechanisms initiated by the activating mutations are thought to includedimer formation and increased intrinsic activity of the kinase domain,both of which result in constitutive ligand-independent kinaseactivation, and possibly altered substrate specificity. More than thirtyactivating mutations of the Kit protein have been associated with highlymalignant tumors in humans.

Accordingly, it has been recognized that inhibitors of receptor tyrosinekinases are useful as selective inhibitors of the growth of mammaliancancer cells. For example, Gleevec™ (also known as imatinib mesylate, orST1571), a 2-phenylpyrimidine tyrosine kinase inhibitor that inhibitsthe kinase activity of the BCR-ABL fusion gene product, was recentlyapproved by the U.S. Food and Drug Administration for the treatment ofCML. Gleevec™, in addition to inhibiting BCR-ABL kinase, also inhibitsthe KIT kinase and PDGF receptor kinase, although it is not effectiveagainst all mutant isoforms of the KIT kinase. Kit ligand-stimulatedgrowth of MO7e human leukemia cells is inhibited by Gleevec™, which alsoinduces apoptosis under these conditions. By contrast, GM-CSF stimulatedgrowth of MO7e human leukemia cells is not affected by Gleevec™.Further, in recent clinical studies using Gleevec™ to treat patientswith GIST, a disease in which KIT kinase is involved in transformationof the cells, many of the patients showed marked improvement.

These studies demonstrate how KIT kinase inhibitors can treat tumorswhose growth is dependent on KIT kinase activity. Other kinaseinhibitors show even greater kinase selectivity. For example, the4-anilinoquinazoline compound Tarceva™ inhibits only EGF receptor kinasewith high potency, although it can inhibit the signal transduction ofother receptor kinases, probably by virtue of the fact that thesereceptors heterodimerize with EGF receptor.

Although anti-cancer compounds such as those described above make asignificant contribution to the art, there is a continuing need forimproved anti-cancer pharmaceuticals, and it would be desirable todevelop new compounds with better selectivity or potency, or withreduced toxicity or side effects.

U.S. Pat. Nos. 5,990,146 and 6,218,388 describe benzimidazoles forinhibiting protein tyrosine kinase mediated cellular proliferation. U.S.Pat. No. 6,348,032 describes method of inhibiting neoplastic cells withbenzimidazole derivatives. International Patent Publication No. WO01/21634 describes benzimidazole derivatives and combinatorial librariesthereof. International Patent Publication No. WO 01/57020 describesindole and benzimidazole inhibitors of factor Xa. International PatentPublication No. WO 00/15222 describes fused pyridine inhibitors of cGMPphosphodiesterase. International Patent Publication No. WO 01/12600describes inhibitors of Factor Xa. International Patent Publication No.WO 97/12613 describes method for treating and preventing inflammationand atherosclerosis.

U.S. Pat. No. 6,316,474 describes 2-benzyl and 2-heteroarylbenzimidazole NMDA/NR2b antagonists. U.S. Pat. No. 6,479,508 describesviral polymerase inhibitors. U.S. Pat. No. 6,444,617 describesfused-heterocycle dicarboxylic acid diamide derivatives or saltsthereof, herbicide and usage thereof. U.S. Pat. Nos. 6,087,380,6,414,008, and 6,469,039 describe disubstituted bicyclic heterocycles.U.S. Pat. No. 5,118,688 describes tetrahydropyridonquinolonederivatives. U.S. Pat. No. 4,975,435 describes certain1H-pyrrolo[3,4-b]quinolin-1-one-9-amino-2,3-dihydro derivatives usefulfor treating anxiety. U.S. Pat. No. 6,548,524 describesortho-sulfonamido bicyclic heteroaryl hydroxamic acids. U.S. Pat. No.6,348,474 describes sulfonamide compounds.

U.S. Pat. Nos. 5,972,980 and 6,001,866 describe method for treating andpreventing inflammation and atherosclerosis. U.S. Pat. No. 5,814,651describes catechol diethers as selective PDEIV inhibitors. U.S. Pat. No.6,329,383 describes 2-amino-5-pyrimidine acetic acid compounds. U.S.Pat. No. 5,688,809 describes 5-heteroarylindole derivatives. EuropeanPatent Application No. EP 0 846 689 describes benzimidazole compounds.International Patent Publication No. WO 00/59888 describesN-benzimidazolylmethyl- and N-indolylmethyl-benzamides and their use asCRF modulators. International Patent Publication No. WO 02/069965describes benzimidazole derivatives as therapeutic agents. InternationalPatent Publication No. WO 02/30886 describes heterocyclic angiogenesisinhibitors. U.S. Pat. No. 6,162,804 describes tyrosine kinaseinhibitors. U.S. Pat. No. 6,465,484 describes angiogenesis inhibitors.International Patent Publication No. WO 00/12089 describes novelangiogenesis inhibitors.

German Patent Publication No. DE 2244908 describes selectively permeablepolymeric membranes. European Patent Application No. EP 0 706 795describes catechol diether compounds as inhibitors of TNF release.International Patent Publication No. WO 02/076960 describes transitionmetal mediated process. International Patent Publication No. WO02/059118 describes process for N-(oxyalkylation) of carboxamides.International Patent Publication No. WO 02/04425 describes viralpolymerase inhibitors. International Patent Publication No. WO 02/083143describes CXCR3 antagonists. International Patent Publication No. WO01/57019 describes indolone and benzimidazolone inhibitors of factor Xa.European Patent Application No. EP 1 085 372 describes photographicmaterial having improved color reproduction. International PatentPublication No. WO 01/14342 describes aminocarbonyl-substitutedbenzimidazole derivatives. International Patent Publication No. WO00/76501 describes IL-8 receptor antagonists.

Thus, it is desirable to develop compounds that exhibit Kit inhibitionin order to treat oncology. Further, such compounds may be active inother kinases such as, for example, GIST, FLT3, Hematopoietic R-PTKs,PDGFR-beta or KDR to add efficacy in mast cell leukemias, small celllung cancer (SCLC), mastocytosis, leukemias, myelodysplastic disorders,or angiogenic dependent diseases.

SUMMARY OF THE INVENTION

Compounds represented by Formula (I):

or a pharmaceutically acceptable salt or N-oxide thereof, are useful inthe treatment of tumors.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a compound represented by Formula(I)

wherein:

R1 is —NR₃R₃₁, —NR₃C(O)R₃₁, —NR₃C(O)OR₃₁, —NR₃SO₂R₃₁, —OR₃, —SR₃,—SO₂R₃, —CO₂R₃, —CO₂H, —CO—NR₃R₃₁, —N(C₀₋₈alkyl)(C₀₋₈alkyl), or —CN,group; except when Y is present and m>1, then R1 is halogen, —CN, NO₂,—C₀₋₈alkyl, —N(C₀₋₈alkyl)(C₀₋₈alkyl), C₂₋₈alkenyl, C₂₋₈alkynyl, —NR₃R₃₁,—NR₃C(O)R₃₁, —NR₃C(O)OR₃₁, —NR₃SO₂R₃₁, —OR₃, —SR₃, —SO₂R₃, —CO₂R₃,—CO₂H, —CO—NR₃R₃₁, cyclyl, or heterocyclyl group;

R2 is H, —C₀₋₈alkyl, or —C₃₋₁₀cycloalkyl;

X is a cyclyl or heterocyclyl group optionally substituted with 1 ormore substituents chosen from H, halogen, NR₃₂R₃₃, NR₃₂COR₃₃,NR₃₂CO2R₃₃, NR₃₂SO₂R₃₃OR₃₂, SR₃₂, SO₂R₃₂, SO₂NR₃₂R₃₃, CO₂R₃₂, CO₂H,CONR₃₂R₃₃, —C₀₋₈alkyl, —C₂₋₈alkenyl, —C₂₋₈alkynyl, CN, CF₃, OCF₃, NO₂,oxo, cyclyl or a heterocyclyl group;

-   Y is absent, or

wherein the point of attachment to X can be from either the left or theright of the linkers as shown;

R_(a) and R_(b) each independently is —C₀₋₈alkyl, —C₂₋₈alkenyl,—C₂₋₈alkynyl, —C₃₋₁₀cycloalkyl, —C₃₋₁₀cycloalkenyl, —C₁₋₈alkoxy,-thioC₁₋₈alkyl, carboxyl, —N(C₀₋₈alkyl)(C₀₋₈alkyl), oxo, or hydroxy; ortaken together with the C to which they are attached, form a saturatedor partially unsaturated 3-10 membered ring optionally containing 0-4 N,O, S, SO, or SO₂ at the ring nodes;

R_(c) and R_(d) each independently is —C₀₋₈alkyl, —C₂₋₈alkenyl, benzyl,or acyl; or taken together, or with R_(a) or R_(b), form a 3-7 memberedsaturated or partially unsaturated ring;

m is 0, 1, 2, 3, 4, or 5;

Z is a cyclyl or heterocyclyl group, optionally substituted with 1 ormore substituents chosen from halogen, NR₃₄R₃₅, NR₃₄COR₃₅, NR₃₄CO2R₃₅,NR₃₄SO₂R₃₅, OR₃₄, SR₃₄, SO₂R₃₄, SO₂NR₃₄R₃₅, CO₂R₃₄, CO₂H, CONR₃₄R₃₅,—C₀₋₈alkyl, —C₂₋₈alkenyl, —C₂₋₈alkynyl, CN, CF₃, NO₂, oxo, cyclyl or aheterocyclyl group; or, when X and Y are present, Z can be —C₁₋₈alkyl or—C₁₋₈alkyl-O—C₁₋₈alkyl; and

R₃, R₃₁, R₃₂, R₃₃, R₃₄ and R₃₅ are independently C₀₋₈alkyl optionallysubstituted with a heterocyclyl or OH substituent;—C₀₋₈alkyl-C₃₋₈cycloalkyl, CF₃, —C₀₋₈alkyl-O—C₀₋₈alkyl,—C₀₋₈alkyl-N(C₀₋₈alkyl)(C₀₋₈alkyl), —C₀₋₈alkyl-S(O)₀₋₂—C₀₋₈alkyl; orheterocyclyl optionally substituted with —C₀₋₈alkyl, cyclyl orsubstituted cyclyl substituent.

In one aspect, the present invention is directed to a compoundrepresented by Formula (I), or a pharmaceutically acceptable salt orN-oxide thereof, wherein R1 is —CONR₃R₃₁; and the other variables are asdescribed above for Formula (I).

In an embodiment, the present invention is directed to a compoundrepresented by Formula (I), or a pharmaceutically acceptable salt orN-oxide thereof, wherein R1 is —CONR₃R₃₁; X is cyclyl; and the othervariables are as described above for Formula (I).

In another embodiment, the present invention is directed to a compoundrepresented by Formula (I), or a pharmaceutically acceptable salt orN-oxide thereof, wherein R1 is —CONR₃R₃₁; X is cyclyl; Y is absent; andthe other variables are as described above for Formula (I).

In yet another embodiment, the present invention is directed to acompound represented by Formula (I), or a pharmaceutically acceptablesalt or N-oxide thereof, wherein R1 is —CONR₃R₃₁; X is cyclyl; Y is

and the other variables are as described above for Formula (I).

In yet another embodiment, the present invention is directed to acompound represented by Formula (I), or a pharmaceutically acceptablesalt or N-oxide thereof, wherein R1 is —CONR₃R₃₁; X is cyclyl; Y is

and the other variables are as described above for Formula (I).

In yet another embodiment, the present invention is directed to acompound represented by Formula (I), or a pharmaceutically acceptablesalt or N-oxide thereof, wherein R1 is —CONR₃R₃₁; X is cyclyl; Y is

and the other variables are as described above for Formula (I).).

In yet another embodiment, the present invention is directed to acompound represented by Formula (I), or a pharmaceutically acceptablesalt or N-oxide thereof, wherein R1 is —CONR₃R₃₁; X is cyclyl; Y is

and the other variables are as described above for Formula (I).

As used herein, unless stated otherwise, “alkyl” as well as other groupshaving the prefix “alk” such as, for example, alkoxy, alkanyl, alkenyl,alkynyl, and the like, means carbon chains which may be linear orbranched or combinations thereof. Examples of alkyl groups includemethyl, ethyl, propyl, isopropyl, butyl, sec- and tertbutyl, pentyl,hexyl, heptyl and the like. “Alkenyl”, “alkynyl” and other like termsinclude carbon chains having at least one unsaturated carbon-carbonbond.

As used herein, “C₀₋₄alkyl” is used to mean an alkyl having 0-4carbons—that is, 0, 1, 2, 3, or 4 carbons in a straight or branchedconfiguration. An alkyl having no carbon is hydrogen when the alkyl is aterminal group. An alkyl having no carbon is a direct bond when thealkyl is a bridging (connecting) group.

The terms “cycloalkyl”, “carbocyclic ring”, cyclic”, or “cyclyl” mean3-10 membered mono or polycyclic aromatic, partially aromatic ornon-aromatic ring carbocycles containing no heteroatoms, and includemono-, bi-, and tricyclic saturated carbocycles, as well as fused andbridged systems. Such fused ring systems can include one ring that ispartially or fully unsaturated, such as a benzene ring, to form fusedring systems, such as benzofused carbocycles. Cycloalkyl includes suchfused ring systems as spirofused ring systems. Examples of cycloalkyland carbocyclic rings include C₃₋₈cycloalkyl such as cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, and decahydronaphthalene,adamantane, indanyl, 1,2,3,4-tetrahydronaphthalene and the like.

The term “halogen” includes fluorine, chlorine, bromine, and iodineatoms.

The term “carbamoyl” unless specifically described otherwise means—C(O)—NH— or —NH—C(O)—.

The term “aryl” is well known to chemists. The preferred aryl groups arephenyl and naphthyl.

The term “hetaryl” is well known to chemists. The term includes 5- or6-membered heteroaryl rings containing 1-4 heteroatoms chosen fromoxygen, sulfur, and nitrogen in which oxygen and sulfur are not next toeach other. Examples of such heteroaryl rings are furyl, thienyl,pyrrolyl, pyrazolyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl,isothiazolyl, triazolyl, oxadiazolyl, thiadiazolyl, tetrazolyl, pyridyl,pyridazinyl, pyrimidinyl, pyrazinyl, and triazinyl. The term “hetaryl”includes hetaryl rings with fused carbocyclic ring systems that arepartially or fully unsaturated, such as a benzene ring, to form abenzofused hetaryl. For example, benzimidazole, benzoxazole,benzothiazole, benzofuran, quinoline, isoquinoline, quinoxaline, and thelike.

Unless otherwise stated, the terms “heterocyclic ring”, “heterocycle”,“heterocyclic”, and “heterocyclyl” are equivalent, and is defined as forcyclic but also contains one or more atoms chosen independently from N,O, and S and their oxides, provided such derivatives exhibit appropriateand stable valencies and excludes moieties containing O—O,S(O)_(n)—S(O)_(n), S(O)_(n)—O bonds where n=0-2. The terms include4-8-membered saturated rings containing one or two heteroatoms chosenfrom oxygen, sulfur, and nitrogen. Examples of heterocyclic ringsinclude azetidine, oxetane, tetrahydrofuran, tetrahydropyran, oxepane,oxocane, thietane, thiazolidine, oxazolidine, oxazetidine, pyrazolidine,isoxazolidine, isothiazolidine, tetrahydrothiophene,tetrahydrothiopyran, thiepane, thiocane, azetidine, pyrrolidine,piperidine, azepane, azocane, [1,3]dioxane, oxazolidine, piperazine,homopiperazine, morpholine, thiomorpholine, and the like. Other examplesof heterocyclic rings include the oxidized forms of thesulfur-containing rings. Thus, tetrahydrothiophene-1-oxide,tetrahydrothiophene-1,1-dioxide, thiomorpholine-1-oxide,thiomorpholine-1,1-dioxide, tetrahydrothiopyran-1-oxide,tetrahydrothiopyran-1,1-dioxide, thiazolidine-1-oxide, andthiazolidine-1,1-dioxide are also considered to be heterocyclic rings.The term “heterocyclic” also includes fused ring systems and can includea carbocyclic ring that is partially or fully unsaturated, such as abenzene ring, to form benzofused heterocycles. For example,3,4-dihydro-1,4-benzodioxine, tetrahydroquinoline,tetrahydroisoquinoline and the like.

Compounds described herein may contain one or more asymmetric centersand may thus give rise to diastereomers and optical isomers. The presentinvention includes all such possible diastereomers as well as theirracemic mixtures, their substantially pure resolved enantiomers, allpossible geometric isomers, and pharmaceutically acceptable saltsthereof. The above Formula I is shown without a definitivestereochemistry at certain positions. The present invention includes allstereoisomers of Formula I and pharmaceutically acceptable saltsthereof. Further, mixtures of stereoisomers as well as isolated specificstereoisomers are also included. During the course of the syntheticprocedures used to prepare such compounds, or in using racemization orepimerization procedures known to those skilled in the art, the productsof such procedures can be a mixture of stereoisomers.

The above Formula I is shown without a definitive stereochemistry atcertain positions. The present invention includes all stereoisomers ofFormula I and pharmaceutically acceptable salts thereof. Further,mixtures of stereoisomers as well as isolated specific stereoisomers arealso included. During the course of the synthetic procedures used toprepare such compounds, or in using racemization or epimerizationprocedures known to those skilled in the art, the products of suchprocedures can be a mixture of stereoisomers.

The invention also encompasses a pharmaceutical composition that iscomprised of a compound of Formula I in combination with apharmaceutically acceptable carrier.

Preferably, the composition is comprised of a pharmaceuticallyacceptable carrier and a non-toxic therapeutically effective amount of acompound of Formula I as described above (or a pharmaceuticallyacceptable salt or N-oxide thereof).

Moreover, within this preferred embodiment, the invention encompasses apharmaceutical composition for the treatment of disease by theinhibition of the c-Kit kinase, which may be a wild-type or mutant formof the protein, comprising a pharmaceutically acceptable carrier and anon-toxic therapeutically effective amount of compound of Formula I asdescribed above (or a pharmaceutically acceptable salt or N-oxidethereof).

The compounds and compositions of the present invention are effectivefor treating mammals such as, for example, humans.

The term “pharmaceutically acceptable salts” refers to salts preparedfrom pharmaceutically acceptable non-toxic bases or acids. When thecompound of the present invention is acidic, its corresponding salt canbe conveniently prepared from pharmaceutically acceptable non-toxicbases, including inorganic bases and organic bases. Salts derived fromsuch inorganic bases include aluminum, ammonium, calcium, copper (ic andous), ferric, ferrous, lithium, magnesium, manganese (ic and ous),potassium, sodium, zinc and the like salts. Particularly preferred arethe ammonium, calcium, magnesium, potassium and sodium salts. Saltsderived from pharmaceutically acceptable organic non-toxic bases includesalts of primary, secondary, and tertiary amines, as well as cyclicamines and substituted amines such as naturally occurring andsynthesized substituted amines. Other pharmaceutically acceptableorganic non-toxic bases from which salts can be formed include ionexchange resins such as, for example, arginine, betaine, caffeine,choline, N′,N′-dibenzylethylenediamine, diethylamine,2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine,ethylenediamine, N

When the compound of the present invention is basic, its correspondingsalt can be conveniently prepared from pharmaceutically acceptablenon-toxic acids, including inorganic and organic acids. Such acidsinclude, for example, acetic, benzenesulfonic, benzoic, camphorsulfonic,citric, ethanesulfonic, fumaric, gluconic, glutamic, hydrobromic,hydrochloric, isethionic, lactic, maleic, malic, mandelic,methanesulfonic, mucic, nitric, pamoic, pantothenic, phosphoric,succinic, sulfuric, tartaric, p-toluenesulfonic acid and the like.Particularly preferred are citric, hydrobromic, hydrochloric, maleic,phosphoric, sulfuric, methanesulfonic, and tartaric acids.

The pharmaceutical compositions of the present invention comprise acompound represented by formula I (or a pharmaceutically acceptable saltor N-oxide thereof) as an active ingredient, a pharmaceuticallyacceptable carrier and optionally other therapeutic ingredients oradjuvants. The compositions include compositions suitable for oral,rectal, topical, and parenteral (including subcutaneous, intramuscular,and intravenous) administration, although the most suitable route in anygiven case will depend on the particular host, and nature and severityof the conditions for which the active ingredient is being administered.The pharmaceutical compositions may be conveniently presented in unitdosage form and prepared by any of the methods well known in the art ofpharmacy.

In practice, the compounds represented by Formula I, or pharmaceuticallyacceptable salts or N-oxides thereof, of this invention can be combinedas the active ingredient in intimate admixture with a pharmaceuticalcarrier according to conventional pharmaceutical compounding techniques.The carrier may take a wide variety of forms depending on the form ofpreparation desired for administration. E.g., oral or parenteral(including intravenous). Thus, the pharmaceutical compositions of thepresent invention can be presented as discrete units suitable for oraladministration such as capsules, cachets or tablets each containing apredetermined amount of the active ingredient. Further, the compositionscan be presented as a powder, as granules, as a solution, as asuspension in an aqueous liquid, as a non-aqueous liquid, as anoil-in-water emulsion, or as a water-in-oil liquid emulsion. In additionto the common dosage forms set out above, the compound represented byFormula I, or a pharmaceutically acceptable salt or N-oxide thereof, mayalso be administered by controlled release means and/or deliverydevices. The compositions may be prepared by any of the methods ofpharmacy. In general, such methods include a step of bringing intoassociation the active ingredient with the carrier that constitutes oneor more necessary ingredients. In general, the compositions are preparedby uniformly and intimately admixing the active ingredient with liquidcarriers or finely divided solid carriers or both. The product can thenbe conveniently shaped into the desired presentation.

Thus, the pharmaceutical compositions of this invention may include apharmaceutically acceptable carrier and a compound or a pharmaceuticallyacceptable salt or N-oxide of Formula I. The compounds of Formula I, orpharmaceutically acceptable salts or N-oxides thereof, can also beincluded in pharmaceutical compositions in combination with one or moreother therapeutically active compounds.

The pharmaceutical compositions of this invention include apharmaceutically acceptable liposomal formulation containing a compoundof Formula I or a pharmaceutically acceptable salt or N-oxide thereof.

The pharmaceutical carrier employed can be, for example, a solid,liquid, or gas. Examples of solid carriers include lactose, terra alba,sucrose, talc, gelatin, agar, pectin, acacia, magnesium stearate, andstearic acid. Examples of liquid carriers are sugar syrup, peanut oil,olive oil, and water. Examples of gaseous carriers include carbondioxide and nitrogen.

In preparing the compositions for oral dosage form, any convenientpharmaceutical media may be employed. For example, water, glycols, oils,alcohols, flavoring agents, preservatives, coloring agents, and the likemay be used to form oral liquid preparations such as suspensions,elixirs and solutions; while carriers such as starches, sugars,microcrystalline cellulose, diluents, granulating agents, lubricants,binders, disintegrating agents, and the like may be used to form oralsolid preparations such as powders, capsules and tablets. Because oftheir ease of administration, tablets and capsules are the preferredoral dosage units whereby solid pharmaceutical carriers are employed.Optionally, tablets may be coated by standard aqueous or nonaqueoustechniques.

A tablet containing the composition of this invention may be prepared bycompression or molding, optionally with one or more accessoryingredients or adjuvants. Compressed tablets may be prepared bycompressing, in a suitable machine, the active ingredient in afree-flowing form such as powder or granules, optionally mixed with abinder, lubricant, inert diluent, surface active or dispersing agent orother such excipient. These excipients may be, for example, inertdiluents such as calcium carbonate, sodium carbonate, lactose, calciumphosphate or sodium phosphate; granulating and disintegrating agents,for example, corn starch, or alginic acid; binding agents, for example,starch, gelatin or acacia; and lubricating agents, for example,magnesium stearate, stearic acid or talc. The tablets may be uncoated orthey may be coated by known techniques to delay disintegration andabsorption in the gastrointestinal tract and thereby provide a sustainedaction over a longer time. For example, a time delay material such asglyceryl monostearate or glyceryl distearate may be used.

In hard gelatin capsules, the active ingredient is mixed with an inertsolid diluent, for example, calcium carbonate, calcium phosphate orkaolin. In soft gelatin capsules, the active ingredient is mixed withwater or an oil medium, for example, peanut oil, liquid paraffin orolive oil. Molded tablets may be made by molding in a suitable machine,a mixture of the powdered compound moistened with an inert liquiddiluent. Each tablet preferably contains from about 0.05 mg to about 5 gof the active ingredient and each cachet or capsule preferablycontaining from about 0.05 mg to about 5 g of the active ingredient.

For example, a formulation intended for the oral administration tohumans may contain from about 0.5 mg to about 5 g of active agent,compounded with an appropriate and convenient amount of carriermaterial, which may vary from about 5 to about 95 percent of the totalcomposition. Unit dosage forms will generally contain between from about1 mg to about 2 g of the active ingredient, typically 25 mg, 50 mg, 100mg, 200 mg, 300 mg, 400 mg, 500 mg, 600 mg, 800 mg, or 1000 mg.

Pharmaceutical compositions of the present invention suitable forparenteral administration may be prepared as solutions or suspensions ofthe active compounds in water. A suitable surfactant can be includedsuch as, for example, hydroxypropylcellulose. Dispersions can also beprepared in glycerol, liquid polyethylene glycols, and mixtures thereofin oils. Further, a preservative can be included to prevent thedetrimental growth of microorganisms.

Pharmaceutical compositions of the present invention suitable forinjectable use include sterile aqueous solutions or dispersions.Furthermore, the compositions can be in the form of sterile powders forthe extemporaneous preparation of such sterile injectable solutions ordispersions. In all cases, the final injectable form must be sterile andmust be effectively fluid for easy syringability. The pharmaceuticalcompositions must be stable under the conditions of manufacture andstorage; thus, preferably should be preserved against the contaminatingaction of microorganisms such as bacteria and fungi. The carrier can bea solvent or dispersion medium containing, for example, water, ethanol,polyol (e.g., glycerol, propylene glycol and liquid polyethyleneglycol), vegetable oils, and suitable mixtures thereof.

Pharmaceutical compositions of the present invention can be in a formsuitable for topical use such as, for example, an aerosol, cream,ointment, lotion, dusting powder, or the like. Further, the compositionscan be in a form suitable for use in transdermal devices. Theseformulations may be prepared, utilizing a compound represented byFormula I of this invention, or a pharmaceutically acceptable salt orN-oxide thereof, via conventional processing methods. As an example, acream or ointment is prepared by admixing hydrophilic material andwater, together with about 5 wt % to about 10 wt % of the compound, toproduce a cream or ointment having a desired consistency.

Pharmaceutical compositions of this invention can be in a form suitablefor rectal administration wherein the carrier is a solid. It ispreferable that the mixture forms unit dose suppositories. Suitablecarriers include cocoa butter and other materials commonly used in theart. The suppositories may be conveniently formed by first admixing thecomposition with the softened or melted carrier(s) followed by chillingand shaping in molds.

In addition to the aforementioned carrier ingredients, thepharmaceutical formulations described above may include, as appropriate,one or more additional carrier ingredients such as diluents, buffers,flavoring agents, binders, surface-active agents, thickeners,lubricants, preservatives (including anti-oxidants) and the like.Furthermore, other adjuvants can be included to render the formulationisotonic with the blood of the intended recipient. Compositionscontaining a compound described by Formula I, or pharmaceuticallyacceptable salts or N-oxides thereof, may also be prepared in powder orliquid concentrate form.

Generally, dosage levels on the order of from about 0.01 mg/kg to about750 mg/kg of body weight per day are useful in the treatment of theabove-indicated conditions, or alternatively about 0.5 mg to about 75 gper patient per day. For example, breast cancer, head and neck cancers,and gastrointestinal cancer such as colon, rectal or stomach cancer maybe effectively treated by the administration of from about 0.01 to 500mg of the compound per kilogram of body weight per day, or alternativelyabout 0.5 mg to about 50 g per patient per day.

Similarly, leukemia, ovarian, bronchial, lung, and pancreatic cancer maybe effectively treated by the administration of from about 0.01 to 500mg of the compound per kilogram of body weight per day, or alternativelyabout 0.5 mg to about 50 g per patient per day.

Mastocytosis/mast cell leukemia, gastrointestinal stromal tumors (GIST),small cell lung carcinoma (SCLC), colon cancer, sinonasal naturalkiller/T-cell lymphoma, testicular cancer (seminoma), thyroid carcinoma,malignant melanoma, ovarian carcinoma, adenoid cystic carcinoma, acutemyelogenous leukemia (AML), breast carcinoma, pediatric T-cell acutelymphoblastic leukemia, angiosarcoma, anaplastic large cell lymphoma,endometrial carcinoma, and prostate carcinoma may be effectively treatedby the administration of from about 0.01 to 500 mg of the compound perkilogram of body weight per day, or alternatively about 0.5 mg to about50 g per patient per day.

It is understood, however, that the specific dose level for anyparticular patient will depend upon a variety of factors including theage, body weight, general health, sex, diet, time of administration,route of administration, rate of excretion, drug combination and theseverity of the particular disease undergoing therapy.

The compounds of the present invention, or pharmaceutically acceptablesalts or N-oxides thereof, can also be effectively administered inconjunction with other cancer therapeutic compounds. For example,cytotoxic agents and angiogenesis inhibiting agents can be advantageousco-agents with the compounds of the present invention. Accordingly, thepresent invention includes compositions comprising the compoundsrepresented by Formula I, or a pharmaceutically acceptable salt orN-oxide thereof, and a cytotoxic agent or an angiogenesis-inhibitingagent. The amounts of each can be therapeutically effective alone—inwhich case the additive effects can overcome cancers resistant totreatment by monotherapy. The amounts of any can also besubtherapeutic—to minimize adverse effects, particularly in sensitivepatients.

It is understood that the treatment of cancer depends on the type ofcancer. For example, lung cancer is treated differently as a first linetherapy than are colon cancer or breast cancer treated. Even within lungcancer, for example, first line therapy is different from second linetherapy, which in turn is different from third line therapy. Newlydiagnosed patients might be treated with cisplatinum containingregimens. Were that to fail, they move onto a second line therapy suchas a taxane. Finally, if that failed, they might get a tyrosine kinaseEGFR inhibitor as a third line therapy. Further, The regulatory approvalprocess differs from country to country. Accordingly, the acceptedtreatment regimens can differ from country to country. Nevertheless, thecompounds of the present invention, or pharmaceutically acceptable saltsor N-oxides thereof, can be beneficially co-administered in conjunctionor combination with other such cancer therapeutic compounds. Such othercompounds include, for example, a variety of cytotoxic agents(alkylators, DNA topoisomerase inhibitors, antimetabolites, tubulinbinders); inhibitors of angiogenesis; and different other forms oftherapies including kinase inhibitors such as Tarceva, monoclonalantibodies, and cancer vaccines. Other such compounds that can bebeneficially co-administered with the compounds of the present inventioninclude doxorubicin, vincristine, cisplatin, carboplatin, gemcitabine,and the taxanes. Thus, the compositions of the present invention includea compound according to Formula I, or a pharmaceutically acceptable saltor N-oxide thereof, and an anti-neoplastic, anti-tumor, anti-angiogenic,or chemotherapeutic agent.

The compounds of the present invention, or pharmaceutically acceptablesalts or N-oxides thereof, can also be effectively administered inconjunction with other therapeutic compounds, aside from cancer therapy.For example, therapeutic agents effective to ameliorate adverseside-effects can be advantageous co-agents with the compounds of thepresent invention.

I. Assay for Inhibition of c-Kit in Intact Cells

The ability of compounds to inhibit the tyrosine kinase activity ofc-Kit was determined in a cell-based ELISA assay using the H526 cellline (ATCC # CRL-5811), which was originally derived from a human smallcell lung cancer. The assay determines the ability of compounds to blockligand-stimulated tyrosine phosphorylation of the wild-type c-Kitreceptor protein that is endogenously expressed in H526 cells. Cells arepre-incubated with compounds at various concentrations prior to additionof stem cell factor (SCF), the ligand for the c-Kit receptor tyrosinekinase. Cell lysates are then prepared and the c-Kit protein is capturedonto a c-Kit antibody-coated 96-well ELISA plate. The phosphotyrosinecontent of the receptor protein is then monitored by quantitation of thedegree of binding of an antibody that recognizes only the phosphorylatedtyrosine residues within the captured protein. The antibody used has areporter enzyme (e.g. horseradish peroxidase, HRP) covalently attached,such that binding of antibody to phosphorylated c-Kit can be determinedquantitatively by incubation with an appropriate HRP substrate.

The stock reagents used are as follows:

Cell Lysis Buffer:

50 mM Tris-HCl, pH 7.4

150 mM NaCl

10% Glycerol

1% Triton X-100

0.5 mM EDTA

1 μg/mL leupeptin

1 μg/mL aprotinin

1 mM Sodium orthovanadate

Anti c-Kit Antibody:

0.5 μg/mL anti c-Kit Ab-3 (Lab Vision, catalog #MS289P1) in 50 mM Sodiumbicarbonate, pH 9.

ELISA Assay Plates:

ELISA assay plates are prepared by addition of 100 μL of anti c-Kitantibody to each well of a 96-well Microlite-2 plate (Dynex, catalog#7417), followed by incubation at 37° C. for 2 h. The wells are thenwashed twice with 300 μL wash buffer.

Plate Wash Buffer:

PBS containing 0.5% Tween-20 (PBST)

Cell Assay Medium:

RPMI with 0.1% BSA

pY20-HRP:

25 ng/mL pY20-HRP (Calbiochem, catalog #525320) in PBS, containing 0.5%Tween-20, 5% BSA, 1 mM Sodium orthovanadate

HRP Substrate:

Chemoluminescent detection reagent (Pierce, catalog #37075)

Assay Protocol:

Cultures of H526 cells, growing in RPMI with 10% fetal calf serum, werecollected by centrifugation, washed twice with PBS, and suspended incell assay medium. Cells were then distributed into a V-bottom 96-wellplate at 7.5×10⁴ cells per well in 100 μL cell assay medium.

Compound dilutions were prepared from 10 mM DMSO stocks by dilution incell assay medium, the final concentration of DMSO in the assay being0.1%. To compound incubation wells, 50 μL of the test compound was added(compounds are assayed at concentrations between 0.1 nM and 100 μM); topositive and negative control wells, 50 μL cell assay medium containing0.1% DMSO was added. The cells were then incubated with compound at 37°C. for 3 h. SCF (R&D Systems, catalog #255-SC-010) was then added inorder to stimulate the Kit receptor and induce its tyrosinephosphorylation. Then, 10 μL of a 1.6 μg/mL solution of SCF in cellassay medium was added to all wells apart from the negative controlwells, and the cells were incubated for an additional 15 min at 37° C.Following the addition of ice-cold PBS, the plate was centrifuged at1000 rpm for 5 min, the medium removed by aspiration, and the cellpellet lysed by the addition of 120 μL ice-cold cell lysis buffer perwell. The plate was kept on ice for 20 min and 100 μL of the celllysates from each well were then transferred to the wells of an ELISAassay plate and incubated at 4° C. for 16 h.

Following incubation of the cell lysates in the ELISA plate, the wellswere washed 4 times with 300 μL wash buffer, then 100 μL of thephosphotyrosine detection antibody pY20-HRP was added to each well andthe plate incubated at rt for 2 h. The wells were then washed 4 timeswith 300 μL wash buffer. Then, 50 μL of the chemiluminescent HRPsubstrate was added to each well for luminometric quantitation of theamount of antiphosphotyrosine-HRP conjugate bound to the plate.

Comparison of the assay signals obtained in the presence of compoundwith those of the positive and negative controls (cells incubated in thepresence or absence of SCF, with no compound added), allows the degreeof inhibition of c-Kit receptor tyrosine phosphorylation to bedetermined over a range of compound concentrations. These inhibitionvalues were fitted to a sigmoidal dose-response inhibition curve todetermine the IC₅₀ values (i.e. the concentration of compound thatinhibits SCF-induced tyrosine phosphorylation of the c-Kit protein by50%).

The EXAMPLES of this invention reduced the level of SCF-induced tyrosinephosphorylation of Kit in intact H526 cells as determined in the aboveassay with IC₅₀ values between 15 μM and 0.1 nM.

EXPERIMENTAL

The EXAMPLES of the present invention were prepared according to thefollowing procedures by the methods illustrated in the followingschemes. Appropriate solvents, temperatures, pressures and otherreaction conditions may be readily selected by one of ordinary skill inthe art. Similarly, suitable starting materials may be commerciallyobtained or readily prepared.

In Scheme 1, diarylamines (III) may be produced from the condensation ofnitropyridines (I, X═F, Cl, Br, OMS, OTs) with substituted anilines(II). Coupling of the anilines (II) may also be achieved where X═I, Br,Cl, OTf by utilisation of Pd(0) mediated Buchwald-Hartwig-typeconditions (such as those described in the Journal of Organic Chemistry(1996), 61(21), 7240) or with Cu(I) catalysis. Reduction of III to givethe diaminopyridines (IV) may be achieved using, for example, hydrogenin the presence of a suitable transition metal catalyst (palladium,platinum, ruthenium, nickel), iron, zinc or tin under acidic conditions,with sodium hydrosulphite or with tin(II)chloride dihydrate. Cyclisationof IV to the benzimidazoles (V) may be achieved by reaction with acorresponding carboxylic acid, acid halide, acid anhydride or anorthoformate (e.g. (MeO)₃CH)) and an acid such as formic orp-toluenesulphonic acid. Under certain conditions used to reduce IIIe.g. iron powder in formic acid, conversion to theimidazo[4,5-b]pyridines V may be achieved in one pot. Also, by inclusionof trimethyl orthoformate into a hydrogenation mixture with III, allowsthe direct conversion to V.

Scheme 2 below shows that N-aryl-3H-imidazo[4,5-b]pyridines (V) (andtheir 1H-isomers Va) may also be formed via the process wherebyimidazo[4,5-b]pyridines (VIII) may be arylated under Pd(0) mediatedconditions similar to those disclosed in Journal of the AmericanChemical Society (2000), 122, 7600. Separation of the isomers V and Vamay be achieved by a number of means known to those skilled in the artincluding, but not limited to, chromatographic means or throughcrystallisation from a suitable solvent. Imidazo[4,5-b]pyridines (VIII)may be produced from the cyclisation of the anilides (VII) with acidssuch as, but not limited to, acetic, p-toluenesulphonic, hydrochloric,sulphuric or phosphoric acid. In turn the anilides (VII) can be preparedby reaction of diaminopyridines with acid halides or anhydrides or withcarboxylic acids in the presence of appropriate coupling reagents knownto those skilled in the art such as, but not limited to, EDC, DCC, HOAt,HOBt, HATU, TBTU, CDI including solid supported versions of thesesolution phase reagents. Where R3=H compounds such as VII may beprepared by formylation of VI with alkyl formates (e.g. methyl formate).In the processes described above, conversion of VI into VII may alsolead to the partial or complete conversion to VIII e.g. when R3=H byheating in the presence of formic acid.

Functionalities R1 and R2, may for the most part be included into thetarget molecules through appropriate choice of starting materials e.g.of type I, II, VI and IX. Where the final functionality is not availabledirectly through this process, or where such functionality may becompromised during the subsequent chemistry to build the final molecule,then alternative functionalities may be used and subsequentlytransformed into the final desired functionality by methods, and atpoints in the sequence, readily determined by one skilled in the art.For example, a non-exhaustive list of such transformations includes theconversions: OMe→OH(BBr₃), NH₂→Cl (NaNO₂, CuCl), Br→CN(Pd₂(dba)₃,Zn(CN)₂, DPPF), Me→CO₂H(KMnO₄), CO₂H→CO₂Me (MeOH, H₂SO₄), OH→OAlkyl(Alkyl halide, base), CO₂H→CONR′R″ (EDC, HOAt, DIPEA, HNR′R″), Br→CO₂Me(Pd₂(dba)₃, DPPF, CO(g), MeOH), Br→CO₂H(^(t)BuLi, CO₂), Ar—H→Ar—Br(NBS), CN→CO₂H (conc. H₂SO₄), Br→NR′R″ (Pd₂(dba)₃, DPPF, HNR′R″). Morespecific and representative examples of the incorporation of suchfunctionality into target molecules are shown below in Schemes 3-5.

5-Bromo-3-nitro-2-pyridol may be reacted with p-toluenesulphonylchloride in the presence of DMAP to give the tosylate IX, which can becondensed with 3-fluoroaniline to give the secondary aniline X.Reduction of this intermediate may be achieved with iron powder inacetic acid and the product XI then cyclised to theimidazo[4,5-b]pyridine with formic acid. Treatment of this material withtert-butyllithium followed by quenching of the intermediate anion withcarbon dioxide and acid gives the carboxylic acid derivative XII. Thismay be coupled with 3-aminomethylpyridine using 1,1′-carbonyldiimidazoleto give amide XIII.

Similarly, in Scheme 4 the tosylate IX can be condensed with4-benzyloxyaniline in ethanol to give nitropyridine XIV. This can bereduced with tin (II) chloride dihydrate in refluxing ethanol to givethe diamine XV, which may be cyclised to the imidazo[4,5-b]pyridine XVIwith trimethyl orthoformate in the presence of p-toluenesulphonic acid.As an alternative to the metalation shown in Scheme 3, a cyano group maybe introduced through Pd(0) mediated means using zinc cyanide to giveXVII, although Rosenmund-von Braun (CuCN) conditions are successfulalso. Acid hydrolysis of the nitrile also facilitates debenzylation togive XVIII, which may be alkylated using, for example, a benzyl bromidederivative in the presence of a base such as sodium hydride, to give onhydrolytic work-up, the ether XIX. 1,1′-Carbonyldiimidazole mediatedcoupling with 2-morpholin-4-ylethylamine provides target compound XX.

Another alternative route employed in the synthesis of derivatisedimidazo[4,5-b]pyridines is shown in Scheme 5. 6-Hydroxynicotinic acid(XXI) may be nitrated in the presence of red fuming nitric acid and theproduct (XXII) chlorinated using PCl₅/POCl₃ followed by careful MeOHquenching to give intermediate XXIII. This may be reacted with ananiline, for example, 4-benzyloxyaniline as described previously to givethe nitro-anilino-pyridines such as XXIV, which can be reduced (e.g. bycatalytic hydrogenation) and cyclised (e.g. trimethyl orthoformate andPTSA) as before to give phenol XXVI. This phenol may be alkylated, forexample with a benzyl bromide derivative in the presence of potassiumcarbonate, and the ester group hydrolysed under acidic conditions andcoupled with an amine such as methylamine using CDI to give target amideXXIX.

Definitions: EDC=ethyl dimethylaminopropylcarbodiimide hydrochloride,HOAt=1-hydroxyazabenzotriazole, HOBt=1-hydroxybenzotriazole,CDI=1,1′-carbonyldiimidazole,TBTU=O-benzotriazole-N,N,N′,N′-tetramethyluronium tetrafluoroborate,HATU=azabenzotriazolyl-N,N,N′,N′-tetramethyluronium hexafluorophosphate,DIPEA=diisopropylethylamine, TEA=triethylamine,DMF=N,N-dimethylformamide, NMP=N-methylpyrrolidinone,DCM=dichloromethane, DMAP=4-dimethylaminopyridine, TFA=trifluoroaceticacid, Boc=^(t)butoxycarbonyl, Fmoc=fluorenylmethyloxycarbonyl,DMSO=dimethylsulphoxide, OMs=OSO₂Me, OTs=OSO₂-(4-Me)Ph, OTf=OSO₂CF₃,DPPF/dppf=1,1′-bis(diphenylphosphino)ferrocene,dba=dibenzylideneacetone, NBS=N-bromosuccimimide, HCl (aq)=aqueoushydrochloric acid, DMA=N,N-dimethylacetamide, MeOH=methanol,EtOH=ethanol, EtOAc=ethyl acetate, THF=tetrahydrofuran, HOAc=aceticacid, DMF=N,N-dimethylformamide, HPLC=high performance liquidchromatography,

Example R13-{4-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-morpholin-4-ylethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide

a) 5-Bromo-3-nitropyridin-2-ol (30.00 g, 0.137 mmol) andp-toluenesulfonyl chloride (30.03 g, 0.158 mmol) were suspended inCH₂Cl₂ under N₂ and treated dropwise with triethylamine (38.2 mL, 0.274mmol) prior to the addition of DMAP (3.35 g, 0.027 mmol). After stirringat rt for 16 h the mixture was diluted with CH₂Cl₂ (500 mL) then washedwith 1M HCl (aq) (2×500 mL) and brine (500 mL). The aqueous layer wasback-extracted with CH₂Cl₂ (200 mL) and the combined organic layersdried over Na₂SO₄, and concentrated in vacuo. The crude material thusisolated was chromatographed over silica gel eluting with 50%EtOAc/hexane to give, on evaporation, a solid which was crystallizedfrom 50% EtOAc/hexane to afford 5-bromo-3-nitropyridin-2-yl4-methylbenzenesulfonate. ¹H NMR (400 MHz, CDCl₃) δ 2.51 (s, 3H), 7.43(dd, 2H, J=8.4, 0.4 Hz), 7.99 (dt, 2H, J=6.8, 2.0 Hz), 8.52 (d, 1H,J=2.4 Hz), 8.60 (d, 1H, J=2.4 Hz).

b) 5-Bromo-3-nitropyridin-2-yl 4-methylbenzenesulfonate (38.2 g, 0.102mmol) and 4-benzyloxyaniline (24.13 g, 0.102 mmol) were suspended in 900mL of toluene under N₂, treated with triethylamine (14.27 mL, 0.102mmol) and the mixture heated at 110° C. for 16 h. Then, the reactionmixture was diluted with CH₂Cl₂ (1 L), washed with 2M HCl (aq) (4×500mL) and brine (500 mL), and the combined organic extracts dried overNa₂SO₄ and then concentrated in vacuo. The crude product thus isolatedwas crystallized twice from ethanol to yieldN-[4-(benzyloxy)phenyl]-5-bromo-3-nitropyridin-2-amine. ¹H NMR (400 MHz,CDCl₃) δ 5.11 (s, 2H), 7.04 (d, 2H, J=9.2 Hz), 7.34-7.50 (m, 7H), 8.48(d, 1H, J=2.4 Hz), 8.66 (d, 1H, J=2.4 Hz), 9.94 (bs, 1H).

c) N-[4-(benzyloxy)phenyl]-5-bromo-3-nitropyridin-2-amine (28.5 g, 0.071mmol) and tin (II) chloride dihydrate (160.67 g, 0.712 mmol) weredissolved in 500 mL ethanol under N₂ and the reaction mixture heated atreflux (70° C.) for 30 min. Sodium bicarbonate was then added to thecooled mixture until the pH was greater than 9.5, and then the mixturewas filtered through celite which was washed with methanol. The combinedorganic phases were concentrated in vacuo before being re-constituted inCH₂Cl₂, drying over Na₂SO₄, and concentration in vacuo to yieldN²-[4-(benzyloxy)phenyl]-5-bromopyridine-2,3-diamine. ¹H NMR (400 MHz,CDCl₃) δ 3.44 (bs, 2H), 5.07 (s, 2H), 6.02 (bs, 1H), 6.97 (dt, 2H,J=5.6, 3.6 Hz), 7.12 (d, 1H, J=2.0 Hz), 7.32 (dt, 2H, J=4.8, 0.4 Hz),7.34-7.48 (m, 5H), 7.84 (d, 1H, J=2 Hz); MS (ES+): m/z 371 [MH⁺], 372(35) [MH²⁺]

d) Trimethyl orthoformate (9.0 mL, 81 mmol) and p-toluenesulphonic acid(384 mg, 2.0 mmol) were added to a solution ofN²-[4-(benzyloxy)phenyl]-5-bromopyridine-2,3-diamine (3 g, 8.1 mmol) indichloromethane (40 mL) and the reaction mixture stirred at rt for 4 h.Next, the precipitated material was collected by filtration, redissolvedin CH₂Cl₂ and the solution washed with 10% NaOH (aq) (200 mL) and brine(200 mL), then dried over MgSO₄ and concentrated in vacuo to afford3-[4-(benzyloxy)phenyl]-6-bromo-3H-imidazo[4,5-b]pyridine. ¹H NMR (400MHz, CDCl₃) δ 5.14 (s, 2H), 7.16 (d, J=8.8 Hz, 2H), 7.33-7.47 (m, 5H),7.58 (d, J=8.8 Hz, 2H), 8.25 (s, 1H), 8.28 (d, J=2 Hz, 2H) and 8.46 (d,J=2 Hz, 2H); MS (ES+): m/z 380 [Br⁷⁹ MH⁺], 382 [Br⁸¹MH⁺].

e) 3-[4-(Benzyloxy)phenyl]-6-bromo-3H-imidazo[4,5-b]pyridine (2 g, 5.26mmol), Zn(CN)₂ (371 mg, 3.16 mmol), Pd₂(dba)₃ (101 mg, 0.11 mmol) anddppf (122 mg, 0.22 mmol) in degassed DMF/H₂O (100:1) (15 mL) was stirredat 120° C. under N₂ for 20 h. The mixture was then cooled to rt andtreated with NH₄Cl:NH₄OH:H₂O (4:1:4) (45 mL) and reheated to 80° C. for30 min and then stirred at 0° C. for another 30 min. The precipitatedsolids were isolated by filtration and purified by chromatography oversilica gel eluting with 50% EtOAc/hexane to give3-[4-(benzyloxy)phenyl]-3H-imidazo[4,5-b]pyridine-6-carbonitrile. ¹H NMR(400 MHz, D6-Acetone) δ 5.16 (s, 2H), 7.18 (d, J=8 Hz, 2H), 7.36-7.47(m, 5H), 7.57 (d, J=8 Hz, 2H), 8.41 (s, 1H), 8.44 (d, J=2 Hz, 1H) and8.70 (d, J=2 Hz, 1H); MS (ES+): m/z 327 [MH⁺].

f) 3-[4-(Benzyloxy)phenyl]-3H-imidazo[4,5-b]pyridine-6-carbonitrile (650mg) in 37% HCl (20 mL) was stirred at 100° C. for 48 h. The reactionmixture was then cooled to rt and crude3-(4-hydroxyphenyl)-3H-imidazo[4,5-b]pyridine-6-carboxylic acid wascollected by filtration. ¹H NMR (400 MHz, D6-DMSO) δ 6.91 (d, J=8 Hz,2H), 7.58 (d, J=8 Hz, 2H), 8.54 (d, J=2 Hz, 1H), 8.86 (s, 1H) and 8.9(d, J=2 Hz, 1H); MS (ES+): m/z 256 [MH⁺].

g) A mixture of3-(4-hydroxyphenyl)-3H-imidazo[4,5-b]pyridine-6-carboxylic acid (54 mg,0.21 mmol), tetrabutylammonium iodide (8 mg, 0.021 mmol),4-(trifluoromethoxy)benzyl bromide (0.13 mL, 0.84 mmol) and sodiumhydride (50.4 mg, 1.26 mmol) in DMF (3 mL) was stirred at rt undernitrogen for 4 h. Then, water (3 mL) was added and the mixture washedwith EtOAc (10 mL). The aqueous phase was acidified with 6N HCl (aq) andthe resulting precipitate isolated by filtration. The EtOAc wash wasconcentrated in vacuo and the residue dissolved in MeOH and stirred with6N NaOH (aq) for 2 h prior to acidification (2M HCl (aq) and filtrationof product. The combined solids were dried in vacuo to give3-{4-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-3H-imidazo[4,5-b]pyridine-6-carboxylicacid. ¹H NMR (400 MHz, D6-DMSO) δ 5.26 (s, 2H), 7.26 (d, J=8.9 Hz, 2H),7.42 (d, J=8.2 Hz, 2H), 7.63 (d, J=8.2 Hz, 2H), 7.82 (d, J=8.9 Hz, 2H),8.61 (d, J=1.6 Hz, 1H), 8.95 (s, 1H), 8.97 (d, J=1.6 Hz, 1H) and 13.2(br.s, 1H); MS (ES+): m/z 430 [MH⁺].

h) A mixture of3-{4-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-3H-imidazo[4,5-b]pyridine-6-carboxylicacid (42 mg, 0.1 mmol), CDI (32.4 mg, 0.2 mmol) and DIPEA (87 μL, 0.5mmol) in dry THF (2 mL) was stirred at 60° C. for 2 h and then treatedwith 2-(morpholin-4-yl)ethylamine (26 μL, 0.2 mmol). After a further 2 hat 60° C. the mixture was concentrated in vacuo and the residuechromatographed over silica gel eluting with 5% MeOH/CHCl₃ to give3-{4-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-morpholin-4-ylethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.¹H NMR (400 MHz, D4-MeOH) δ 2.57 (br.s, 4H), 2.65 (t, J=8 Hz, 2H), 3.60(t, J=8 Hz, 2H), 3.71 (t, J=8 Hz, 4H), 5.21 (s, 2H), 7.22 (dd, J=6.8 and2 Hz, 2H), 7.30 (d, J=8.4 Hz, 2H), 7.59 (d, J=8.8 Hz, 2H), 7.71 (dd,J=6.8 and 2 Hz, 2H), 8.57 (d, J=1.6 Hz, 1H), 8.71 (s, 1H) and 8.90 (d,J=1.6 Hz, 1H); MS (ES+): m/z 542 [MH⁺].

The following examples were prepared according to the proceduredescribed above for EXAMPLE R1, utilising the appropriate aniline andamine in place of 4-benzyloxyaniline (step a)) and2-(morpholin-4-yl)ethylamine (step h)), respectively.

Example R2

3-{4-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-methoxyethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 487 [MH⁺]

Example R3

3-{3-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-(pyridine-3-ylmethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 520 [MH⁺]

Example R4

3-{3-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-methoxyethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 487 [MH⁺]

Example R5

3-{4-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-(3-(4-methylpiperazin-1-yl)propyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 569 [MH⁺]

Example R6

3-{4-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-dimethylaminoethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 500 [MH⁺]

Example R7

3-{4-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-piperidin-1-ylethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 540 [MH⁺]

Example R8

3-{4-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-(pyridine-3-ylmethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 520 [MH⁺]

Example R9

3-{4-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-methyl-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 443 [MH⁺]

Example R10

3-{4-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-ethyl-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 457 [MH⁺]

Example R11

3-{4-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-pyrrolidin-1-ylethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 526 [MH⁺]

Example R12

3-{3-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-methyl-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 443 [MH⁺]

Example R13

3-{3-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-ethyl-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 457 [MH⁺]

Example R14

3-{3-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-(3-methoxypropyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 501 [MH⁺]

Example R15

3-{3-[(4-(Trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-dimethylaminoethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.MS (ES+): m/z 500 [MH⁺]

Example R16

3-(4-Methoxyphenyl)-N-(pyridin-3-ylmethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.¹H NMR (400 MHz, CD₃OD/CDCl₃): δ 3.87 (3H, s), 4.64 (2H), 7.10 (2H, d,J=9.0 Hz), 7.36 (1H, dd, J=5.0 Hz, 7.9 Hz), 7.61 (2H, d, J=9.0 Hz), 7.83(1H, dt, J=1.6 Hz, 7.8 Hz), 8.41 (1H, dd, J=1.3 Hz, 4.8 Hz), 8.49 (1H,s), 8.55 (1H, br), 8.59 (1H, d, J=2.0 Hz), 8.95 (1H, d, J=2.0 Hz); MS(ES+): m/z 360 [MH^(+])

Example R17

3-(4-Methoxyphenyl)-N-(2-morpholin-4-ylethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.¹H NMR (400 MHz, CDCl₃): δ 2.54 (4H, br), 2.65 (2H, t, J=6.0 Hz), 3.62(2H, quart, J=5.5 Hz), 3.89 (3H, s), 6.94 (1H, br), 7.10 (2H, d, J=8.9Hz), 7.61 (2H, d, J=8.9 Hz), 8.35 (1H, s), 8.53 (1H, d, J=1.9 Hz), 8.91(1H, J=1.9 Hz); MS (ES+): m/z 382 [MH⁺]

Example R18

3-(4-Methoxyphenyl)-N-(pyridin-2-ylmethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.¹H NMR (400 MHz, CDCl₃): δ 3.90 (3H, s), 4.83 (2H, d, J=4.7 Hz), 7.11(2H, d, J=8.9 Hz), 7.24-7.28 (1H, m), 7.38 (1H, d, J=7.8 Hz), 7.63 (2H,d, J=8.9 Hz), 7.73 (1H, td, J=1.6 Hz, 7.7 Hz), 7.98 (1H, br), 8.37 (1H,s), 8.58 (1H, d, J=4.7 Hz), 8.67 (1H, d, J=1.9 Hz), 9.04 (1H, d, J=1.9Hz); MS (ES+): m/z 360 [MH⁺]

Example R19

3-(4-Methoxyphenyl)-N-(3-methoxypropyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide.¹H NMR (400 MHz, CDCl₃): δ 1.91 (2H, quint, J=5.5 Hz), 3.41 (3H, s),3.61 (2H, t, J=5.5 Hz), 3.66 (2H, t, J=5.4 Hz), 3.89 (3H, s), 7.10 (2H,d, J=8.9 Hz), 7.21 (br), 7.61 (2H, d, J=8.9 Hz), 8.34 (1H, s), 8.52 (1H,d, J=2.0 Hz), 8.90 (1H, d, J=1.9 Hz); MS (ES+): m/z 341 [MH⁺]

As an alternative route to the imidazopyrides herein described, thefollowing route was also applied toward the synthesis of keyintermediate XXVI.

6-Hydroxy-5-nitronicotinic acid (XXII): To a 250 mL flask were added6-hydroxynicotinic acid (20 g, Aldrich) and 100 mL of red fuming nitricacid. The mixture was slowly heated to 50° C. (bath temperature) andstirred at this temperature for 8 h. Then the temperature was slowlyraised to 80° C. and the mixture was stirred for another 7 h. Themixture was cooled to rt overnight and the yellow precipitate wascollected by filtration, washed with water (10 mL) and dried.LC-MS: >95% pure. ¹H NMR (CD₃OD, 400 MHz): δ=8.45 (d, J=2.5 Hz, 1H),8.85 (d, J=2.5 Hz, 1H).

6-Chloro-5-nitronicotinic acid methyl ester (XXIII): A suspension of6-hydroxy-5-nitro-nicotinic acid (1.1 g, 6.0 mmol) and PCl₅ (3.75 g,18.0 mmol) in POCl₃ (5 mL) was stirred at 100° C. for 2 h. Excessivephosphorus oxychloride was evaporated under reduced pressure. Theresidue was dissolved in 10 mL of anhydrous ether and cooled to 0° C.,then 10 mL of methanol was added dropwise. 10 min later, the ether wasevaporated under reduced pressure at rt. The remaining methanol solutionwas diluted with water (40 mL), and the light-yellow solid was collectedby filtration. ¹H NMR (CDCl₃, 400 MHz): δ=4.03 (s, 3H), 8.77 (d, J=2.1Hz, 1H), 9.18 (d, J=2.1 Hz, 1H).

6-(4-Benzyloxyphenylamino)-5-nitronicotinic acid methyl ester (XXIV): Toa solution of 6-chloro-5-nitro-nicotinic acid methyl ester (216 mg, 1.0mmol) and 4-benzyloxyaniline hydrochloride (280 mg, 1.2 mmol) in MeOH(10 mL) was added ^(i)Pr₂NEt (0.35 mL, 2.0 mmol). The resulting mixturewas stirred at rt overnight, a red solid precipitated from the mixture,which was collected by filtration. MS (ES, Pos.): m/z 380 [MH⁺]. ¹H NMR(CDCl₃, 400 MHz): δ=3.94 (s, 3H), 5.10 (s, 2H), 7.03 (d, J=8.8 Hz, 2H),7.38-7.46 (m, 5H), 7.50 (d, J=8.8 Hz, 2H), 9.01 (d, J=2.0 Hz, 1H), 9.08(d, J=2.0 Hz, 1H), 10.2 (br s, 1H).

3-(4-Hydroxyphenyl)-3H-imidazo[4,5-b]pyridine-6-carboxylic acid methylester (XXVI): To a suspension of XXIV (235 mg, 0.62 mmol) in MeOH (3 mL)and ethyl acetate (3 mL) was added 10% Pd—C (47 mg) under nitrogenatmosphere. The resulting mixture was hydrogenated at rt overnight. Thecatalyst was removed by filtration under nitrogen and washed withmethanol, the filtrate was concentrated under reduced pressure to give awhite solid. MS (ES, Pos.): m/z 260 [MH⁺]. The hydrogenation product wassuspended in trimethyl orthoformate (5 mL), and p-toluenesulfonic acidmonohydrate (12 mg, 0.062 mmol) was added. The resulting mixture wasstirred at rt overnight. The white solid was collected by filtration. MS(ES, Pos.): m/z 270 [MH⁺]. ¹H NMR (CD₃OD, 400 MHz): δ=3.99 (s, 3H), 7.00(d, J=8.8 Hz, 2H), 7.59 (d, J=8.8 Hz, 2H), 8.71 (d, J=1.8 Hz, 1H), 8.72(s, 1H), 9.05 (d, J=1.8 Hz, 1H).

1. A compound represented by Formula (I)

wherein: R1 is —NR₃R₃₁, —NR₃C(O)R₃₁, —NR₃C(O)OR₃₁, —NR₃SO₂R₃₁, —OR₃,—SR₃, —SO₂R₃, —CO₂R₃, —CO₂H, —CO—NR₃R₃₁, —N(C₀₋₈alkyl)(C₀₋₈alkyl), or—CN, group; except when Y is present and m>1, then R1 is halogen, —CN,NO₂, —C₀₋₈alkyl, —N(C₀₋₈alkyl)(C₀₋₈alkyl), C₂₋₈alkenyl, C₂₋₈alkynyl,—NR₃R₃₁, —NR₃C(O)R₃₁, —NR₃C(O)OR₃₁, —NR₃SO₂R₃₁, —OR₃, —SR₃, —SO₂R₃,—CO₂R₃, —CO₂H, —CO—NR₃R₃₁, cyclyl, or heterocyclyl group; R2 is H,—C₀₋₈alkyl, or —C₃₋₁₀cycloalkyl; X is a cyclyl or heterocyclyl groupoptionally substituted with 1 or more substituents chosen from H,halogen, NR₃₂R₃₃, NR₃₂COR₃₃, NR₃₂CO2R₃₃, NR₃₂SO₂R₃₃ OR₃₂, SR₃₂, SO₂R₃₂,SO₂NR₃₂R₃₃, CO₂R₃₂, CO₂H, CONR₃₂R₃₃, —C₀₋₈alkyl, —C₂₋₈alkenyl,—C₂₋₈alkynyl, CN, CF₃, OCF₃, NO₂, oxo, cyclyl or a heterocyclyl group; Yis

wherein the point of attachment to X can be from either the left or theright of the linkers as shown; R_(a) and R_(b) each independently is—C₀₋₈alkyl, —C₂₋₈alkenyl, —C₂₋₈alkynyl, —C₃₋₁₀cycloalkyl,—C₃₋₁₀cycloalkenyl, —C₁₋₈alkoxy, -thioC₁₋₈alkyl, carboxyl,—N(C₀₋₈alkyl)(C₀₋₈alkyl), oxo, or hydroxy; or taken together with the Cto which they are attached, form a saturated or partially unsaturated3-10 membered ring optionally containing 0-4 N, O, S, SO, or SO₂ at thering nodes; R_(c) and R_(d) each independently is —C₀₋₈alkyl,—C₂₋₈alkenyl, benzyl, or acyl; or taken together, or with R_(a) orR_(b), form a 3-7 membered saturated or partially unsaturated ring; m is0, 1, 2, 3, 4, or 5; Z is a cyclyl or heterocyclyl group, optionallysubstituted with 1 or more substituents chosen from halogen, NR₃₄R₃₅,NR₃₄COR₃₅, NR₃₄CO2R₃₅, NR₃₄SO₂R₃₅, OR₃₄, SR₃₄, SO₂R₃₄, SO₂NR₃₄R₃₅,CO₂R₃₄, CO₂H, CONR₃₄R₃₅, —C₀₋₈alkyl, —C₂₋₈alkenyl, —C₂₋₈alkynyl, CN,CF₃, NO₂, oxo, cyclyl or a heterocyclyl group; or, when X and Y arepresent, Z can be —C₁₋₈alkyl or —C₁₋₈alkyl-O—C₁₋₈alkyl; and R₃, R₃₁,R₃₂, R₃₃, R₃₄ and R₃₅ are independently C₀₋₈alkyl optionally substitutedwith a heterocyclyl or OH substituent; —C₀₋₈alkyl-C₃₋₈cycloalkyl, CF₃,—C₀₋₈alkyl-O—C₀₋₈alkyl, —C₀₋₈alkyl-N(C₀₋₈alkyl)(C₀₋₈alkyl),C₀₋₈alkyl-S(O)₀₋₂—C₀₋₈alkyl; or heterocyclyl optionally substituted with—C₀₋₈alkyl, cyclyl or substituted cyclyl substituent; or apharmaceutically acceptable salt or N-oxide thereof.
 2. The compoundaccording to claim 1, or a pharmaceutically acceptable salt or N-oxidethereof, wherein R₁ is —CONR₃R₃₁.
 3. The compound according to claim 2,or a pharmaceutically acceptable salt or N-oxide thereof, wherein X iscyclyl. 4-5. (canceled)
 6. The compound according to claim 3, or apharmaceutically acceptable salt or N-oxide thereof, wherein Y is


7. The compound according to claim 3, or a pharmaceutically acceptablesalt or N-oxide thereof, wherein Y is


8. The compound according to claim 3, or a pharmaceutically acceptablesalt or N-oxide thereof wherein Y is


9. A composition comprising a compound according to claim 1, or apharmaceutically acceptable salt or N-oxide thereof, and apharmaceutically acceptable carrier.
 10. A composition comprising acompound according to claim 1, or a pharmaceutically acceptable salt orN-oxide thereof; and an anti-neoplastic, anti-tumor, anti-angiogenic, orchemotherapeutic agent.
 11. A composition comprising a compoundaccording to claim 1, or a pharmaceutically acceptable salt or N-oxidethereof, and a cytotoxic cancer therapeutic agent.
 12. A compositioncomprising a compound according to claim 1, or a pharmaceuticallyacceptable salt or N-oxide thereof, and an angiogenesis inhibitingcancer therapeutic agent.
 13. A compound selected from:3-{4-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-morpholin-4-ylethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{4-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-methoxyethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{3-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-(pyridine-3-ylmethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{3-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-methoxyethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{4-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-(3-(4-methylpiperazin-1-yl)propyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{4-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-dimethylaminoethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{4-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-piperidin-1-ylethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{4-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-(pyridine-3-ylmethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{4-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-methyl-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{4-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-ethyl-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{4-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-pyrrolidin-1-ylethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{3-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-methyl-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{3-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-ethyl-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{3-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-(3-methoxypropyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-{3-[(4-(trifluoromethoxy)benzyl)oxy]phenyl}-N-(2-dimethylaminoethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-(4-methoxyphenyl)-N-(pyridin-3-ylmethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-(4-methoxyphenyl)-N-(2-morpholin-4-ylethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-(4-methoxyphenyl)-N-(pyridin-2-ylmethyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;3-(4-methoxyphenyl)-N-(3-methoxypropyl)-3H-imidazo[4,5-b]pyridine-6-carboxamide;or a pharmaceutically acceptable salt, or N-oxide, thereof. 14-21.(canceled)